Parsec

A unit of length, 1 parsec or 1 pc = 3.085 68 x 10¹⁶ meters. It is defined by the fact that an object at a distance of 1 parsec has a yearly parallax of one [second of an arc]?. In astronomy, nowadays the parsec is preferred to the light year. A parsec is approximately 3.26 light years.

see also conversion of units, astronomical unit